A keyboard apparatus of this type is conventionally provided with a plurality of keyboard switches disposed on a board in a predetermined positional relationship, and the switches each are provided with a key-top mounted thereon, wherein it is adapted such that depression of one key-top out of the plurality of key-tops causes a movable contact in the switch to come in contact with a fixed contact, in the switch, and the contact therebetween allows a keyed signal to be output to the host side to operate electronic equipment.
Since the keyboard apparatus of the conventional type has been provided with a plurality of switches each having a movable contact and a fixed contact, which are adapted to make an electrical contact therebetween, such an apparatus has often created a problem hindering the operation thereof when dirt or the like attaches to the contacts to produce a bad contact therebetween and this reduces reliability of any keyboard operation. Such an apparatus has also had such a problem that it requires a large number of movable and fixed contacts, which has increased the number of the component parts used therein and raised the cost of the production.